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Mottinger, N. A.

Publications and source records attributed to Mottinger, N. A..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2008

Kaguya Orbit Determination from JPL

Selene (re-named 'Kaguya' after launch) is an unmanned mission to the Moon navigated, in part, by JPL personnel. Launched by an H-IIA rocket on September 14, 2007 from Tanegashima Space Center, Kaguya entered a high, Earth-centered phasing orbit with apogee near the radius of the Moon's orbit. After 19 days and two orbits of Earth, Kaguya entered lunar orbit. Over the next 2 weeks the spacecraft decreased its apolune altitude until reaching a circular, 100 kilometer altitude orbit. This paper describes NASA/JPL's participation in the JAXA/Kaguya mission during that 5 week period, wherein JPL provided tracking data and orbit determination support for Kaguya.

lunar navigation↗
NASA NTRS1992

Orbit determination for Magellan and Pioneer 12 using same-beam interferometry

Simultaneous tracking of two spacecraft in orbit about a distant planet, by two widely-separated earth-based radio antennas, provides more accurate positioning information than can be obtained by tracking each spacecraft separately. A demonstration of this tracking technique, referred to as Same-Beam Interferometry (SBI), is in progress using the Magellan and Pioneer 12 orbiters at Venus. Signals from both spacecraft fall within the same beamwidth of the earth-based tracking antennas. The plane-of-sky position difference between spacecraft is precisely determined by double-differenced phase measurements. This data type complements line-of-sight Doppler. Data were collected from Magellan and Pioneer 12 on Aug. 11-12, 1990, shortly after Magellan was inserted into Venus orbit. Orbits for both spacecraft were fit with one day data arc using Doppler and SBI data and compared to orbits fit to only Doppler data. The Doppler plus SBI orbits show improved orbit-to-orbit consistency over the Doppler-only orbits.

Folkner, W. M.↗
NASA NTRS1988

PSA: A program to streamline orbit determination for launch support operations

An interactive, menu driven computer program was written to streamline the orbit determination process during the critical launch support phase of a mission. Residing on a virtual memory minicomputer, this program retains the quantities in-core needed to obtain a least squares estimate of the spacecraft trajectory with interactive displays to assist in rapid radio metric data evaluation. Menu-driven displays allow real time filter and data strategy development. Graphical and tabular displays can be sent to a laser printer for analysis without exiting the program. Products generated by this program feed back to the main orbit determination program in order to further refine the estimate of the trajectory. The final estimate provides a spacecraft ephemeris which is transmitted to the mission control center and used for antenna pointing and frequency predict generation by the Deep Space Network. The development and implementation process of this program differs from that used for most other navigation software by allowing the users to check important operating features during development and have changes made as needed.

Legerton, V. N.↗
NASA NTRS1986

Giotto navigation support

Cooperative efforts between NASA and the European Space Agency (ESA) in supporting the flight of Giotto to Halley's Comet included prelaunch checks of ESA navigation software and delivery of validated DSN radio metric tracking data during the mission. Effects of drag from passing through the coma are seen in data received pre and post encounter. The post encounter Giotto trajectory provides a solar occultation in January 1988, prior to returning to the Earth in 1990 for possible retargeting to yet another comet.

Mottinger, N. A.↗
NASA NTRS1985

Venus Gravity: Global Field Results

The Pioneer Venus Orbiter has provided a vast amount of gravity data, since March 1979. High resolution results have revealed the high correlation between topography and gravity. These data were acquired at relatively low spacecraft altitudes (150 km) where atmospheric effects and high frequency variations were significant and modelling with global spherical harmonics was difficult. During 1982 data were acquired over a complete Venus rotation where the lowest altitudes were 1000 km or more, thus removing atmospherics and high frequency gravity effects. These data that have been reduced to produce a tenth degree and order spherical harmonic model of the global gravity field of Venus. The reduction technique used a least squares where 78 independent arcs of data were combined in a simultaneous inversion. The tenth degree and order gravity field solution has 117 parameters describing the spherical harmonic coefficients. This provides approximately 1800 km feature resolution. These coefficients are presented as a geoid map.

Mottinger, N. A.↗
NASA NTRS1985

Venus gravity - A harmonic analysis and geophysical implications

An improved theoretical model of Venusian global gravity has been obtained by fitting a tenth degree spherical harmonic series to 78 orbital arcs of Doppler tracking data from the Pioneer Venus Orbiter. Maps of the free-air anomaly and its formal error are presented. Isostatic anomaly and 'Geoid' maps are also presented, and their geophysical implications are discussed in details. Comparison with equivalent resolution topographic models reveals a strong correlation between long wavelength gravity and the topography of Venus. Analysis of the second degree harmonics showed two aspects of the orientation of the inertial axes of Venus: (1) a significant (about three degrees) departure of the axis of greatest inertia from the rotational axis; and (2) a near alignment of the axis of least inertia with the location of the subterrestrial point at the time of the next inferior conjunction with earth (December 16, 2101). A series of contour maps of the Venusian free-air anomalies is provided.

Mottinger, N. A.↗
NASA NTRS1984

Venus - Ishtar gravity anomaly

The gravity anomaly associated with Ishtar Terra on Venus is characterized, comparing line-of-sight acceleration profiles derived by differentiating Pioneer Venus Orbiter Doppler residual profiles with an Airy-compensated topographic model. The results are presented in graphs and maps, confirming the preliminary findings of Phillips et al. (1979). The isostatic compensation depth is found to be 150 + or - 30 km.

Sjogren, W. L.↗
NASA NTRS1983

Venus gravity field - Pioneer Venus Orbiter navigation results

The gravity field of Venus has been modeled by a spherical harmonic expansion of the potential to degree and order seven. The estimates of these coeficients were obtained by combining information from 43 short arcs (4 hr) of line-of-sight Doppler data centered at periapsis. The data arcs were distributed in longitude and time over more than two circulations of Venus by the Pioneer Venus Orbiter subperiapsis point which was confined to the band of latitudes from 14 deg N to 17 deg N. Convergence of the solution has been assured by iterating upon the initial estimate. All estimates were performed with zero a priori information on the gravity coefficients. Since the altitude of periapsis for most of the orbits was within the sensible Venusian atmosphere, drag effects on the estimated harmonics have been removed using an exponential atmosphere density model. Estimates of the mass parameter (GM) of Venus using this dataset are also evaluated.

Williams, B. G.↗
NASA NTRS1983

Venus gravity anomalies and their correlations with topography

This report provides a summary of the high-resolution gravity data obtained from the Pioneer Venus Orbiter radio tracking data. Gravity maps, covering a 70 deg latitude band through 360 deg of longitude, are displayed as line-of-sight and vertical gravity. Topography converted to gravity and Bouguer gravity maps are also shown in both systems. Topography to gravity ratios are made over several regions of the planet. There are markedly different ratios for the Aphrodite area as compared to the Beta and Atla areas.

Sjogren, W. L.↗
NASA NTRS1983

Radio metric orbit determination for the Giotto mission to Comet Halley

An international fleet of five spacecraft will fly past Comet Halley as it travels through the inner solar system in early 1986. This paper discusses orbit determination problems associated with the Giotto spacecraft, sponsored by the European Space Agency. The large number of spin axis precession maneuvers required to maintain the desired spacecraft attitude creates a new kind of radio metric orbit determination problem for this mission. This paper investigates the accuracy with which the Giotto spacecraft orbit can be determined relative to the earth or the sun, and establishes the sensitivity of this accuracy to the selection of the parameters to be estimated, the form of estimator used, the number of tracking stations employed, the length of the data arc, the selection of data types processed, and the levels of various error sources.

Wood, L. J.↗
NASA NTRS1982

Venus gravity - Analysis of Beta Regio

Radio tracking data acquired over Beta Regio were analyzed to obtain a surface mass distribution from which a detailed vertical gravity field was derived. In addition, a corresponding vertical gravity field was evaluated solely from the topography of the Beta region. A comparison of these two maps confirms the strong correlation between gravity and topography which was previously seen in line-of-sight gravity maps. It also demonstrates that the observed gravity is a significant fraction of that predicted from the topography alone. The effective depth of complete isostatic compensation for the Beta region is estimated to be 330 km, which is somewhat deeper than that found for other areas of Venus.

Esposito, P. B.↗
NASA NTRS1979

Interplanetary orbit determination

A general description of the Viking interplanetary orbit determination activity extending from launch to Mars encounter is given. The emphasis is on the technical fundamentals of the problem, basic strategies and data types used, quantitative results, and specific conclusions derived from the inflight experience. Special attention is given to the use of the spacecraft-based optical measurements and their first application as a principal navigational data type for an interplanetary mission. The optical-based orbit determination, in fact, was the primary contributor to the exceptional interplanetary navigation accuracy experienced by both Viking missions. The Viking application of optical orbit determination relied in large part on the technology developed and demonstrated by the Mariner 9 Optical Navigation Demonstration.

Rourke, K. H.↗
NASA NTRS1977

The determination of the interplanetary orbits of Vikings 1 and 2

A description is presented of the navigation-related events of the Viking Mars mission. Orbit determination system fundamentals are discussed, taking into account the trajectory models, observation models, radio data models, range considerations, optical data models, filter models, the orbit determination process, critical orbit determination inputs, and orbit determination errors. Attention is also given to questions of orbit determination strategy, orbit determination results, optical measurements processing, aspects of approach orbit determination evaluation, and the orbit determination software system.

Rourke, K. H.↗
NASA NTRS1977

National geodetic satellite program, part 1

Determinations of tracking station locations and the gravitational constant of the earth, based on Doppler-tracking data from lunar and planetary spacecraft are presented. Two-way Doppler data obtained by the Deep Space Network of the Jet Propulsion Laboratory (JPL) were used. The Deep Space Station instrumentation that JPL employed is described. How the stations were located is detailed, and the data used are discussed. Results are given together with an analysis of the errors.

Esposito, P. B.↗
NASA NTRS1974

Station locations

The extended process of providing station location estimates for use in orbit determination at launch and during the course of the mission, is outlined. Station location sets provided for Mariner Mars 1971 navigation support are given. Data cover set construction, basis for construction, and a comparison of estimated sets with final sets.

Mottinger, N. A.↗
NASA NTRS1973

Interplanetary orbit determination

The logistical aspects of orbit determination (OD) in the interplanetary phase of the Mariner Mars 1971 mission are described and the working arrangements for the OD personnel, both within the Navigation Team and with outside groups are given. Various types of data used in the OD process are presented along with sources of the data. Functional descriptions of the individual elements of the OD software and brief sketches of their modes of operation are provided.

Zielenbach, J. W.↗